To most of the world, he was “that Aussie hunk who dates Miley Cyrus.” But with his star turn in The Hunger Games, which is almost certain to be a monster hit, Liam Hemsworth will step out of his girlfriend’s shadow — and perhaps, down the aisle with her.

“They’re still keeping it a big secret, but they’re seriously talking marriage,” an insider tells OK!. “Liam is crazy about her, though he hasn’t proposed formally yet.”

To be sure, Liam, 22, and 19-year-old Miley have had their ups and downs — breakups and bad press over Miley’s photographed indiscretions. One reason her parents, Billy Ray and Tish, would be thrilled to have Liam as a son-in-law, the insider says, is that they believe he’s a good influence on their sometimes-wayward daughter.

“The whole family loves him, the source tells OK!. “They know Miley’s no angel, but she’s much calmer with him in her life.”

Expect the couple to wed down South, in Miley’s hometown of Franklin, Tenn., or at Tybee Island, Ga., where she and Liam fell in love while filming 2010’s The Last Song.

Of course, the pair already cohabitate. “They love living together,” the insider tells OK!. “Miley is busy redecorating, and Liam is gearing up for The Hunger Games. They’re just really happy, and both of them seem sure they’ve met their match.”

FOR MORE ON LIAM & MILEY'S WEDDING PLANS, CHECK OUT THE NEW ISSUE OF OK!, ON NEWSTANDS NOW!